The present invention relates to Digital TV decoding systems, and more particularly to a Digital TV decoding system that incorporates a multiple transport stream decryption card.
A CableCARD, or Point of Decryption card (POD) is a security module that enables a cable line to be directly plugged into a television set, without requiring a set-top box. The CableCARD provides conditional access and network connection for the television set, by decrypting received transport streams. Conventionally, CableCARDS are capable of processing single streams, meaning they can only decrypt/decode one transport stream at a time. For example, as defined by the CableCARD Interface 1.0 Specification, the CableCARDS are implemented for single-stream decryption/decoding. Current digital technology, however, requires multiple-stream cards in order to perform all digital functions, such as displaying one stream while recording another, or for picture in picture (PIP) mode. To meet these demands, manufacturers have developed a multiple point of decryption (M-POD) card that has the ability of decrypting multiple transport streams, and can operate in both Single-Stream mode and Multi-Stream mode. For example, as defined by the CableCARD Interface 2.0 Specification, the M-POD card is capable of receiving and processing multiple transport streams. The new standard therefore will also enable two-way functions, such as pay-per-view, Video On Demand, and electronic program guides.
It is desired to provide a novel multiple transport stream decrypting and decoding architecture that can perform the decryption efficiently with reduced hardware complexity.